Pottery press



Feb. 5, 1957 c. P. RUMBERGER 2,779,989

- POTTERY PRESS Filed Feb. 11, 1952 2 Sheets-Sheet 1 IN V EN TOR.

C/reszerPgQl/mber er [or/fey Feb. 5, 1957 c. P. RUMBERGER 2,779,989

POTTERY PRESS Filed Feb. 11, 1952 2 Sheets-Sheet 2 IN VEN TOR.

L. C7785 ZemPKa/wber er if BY ww aw attorney United States Patent POTTERY PRESS Chester P. Rumberger, Canonsburg, Pa., assignor to Elmer W. Thompson, Canonsburg, Pa.

Application February 11, 1952, Serial No. 271,604

2 Claims. (Cl. 25--27) This invention relates generally to pottery manufacture, and, more particularly, to a hydraulic press for dry pressing or squeezing out pottery ware, especially cups and the like with or without integral handles.

An outstanding disadvantage of commonly used presses for the manufacture of pottery ware resides in the amount of handling or labor required for making the finished product. Generally a bowl is first shaped and thereafter a handle is separately shaped and attached to the bowl, thus requiring a number of manual operations.

There is a natural preference for chinaware as distinguished from earthenware. However, the substantial additional cost for manufacturing china ware has restricted its use considerably.

An object of the present invention is to provide a novel pottery press which is devoid of the above-mentioned disadvantages of commonly used presses and methods.

Another specific object of the present invention is to provide a novel hydraulic press having dies of such construction as to enable the pressing or molding of a cup with a handle through which a hole extends by a single pressing operation so as to greatly speed up production.

Other objects and advantages of the present invention will become apparent from a study of the following description taken with the accompanying drawings wherein:

Figure 1 is a front elevational view of a hydraulic press for dry pressing cups and similar articles of pottery;

Figure 2 is a side elevational view of the hydraulic press shown in Figure 1;

Figure 3 is an enlarged side elevational view of the split top die;

Figure 4 is a plan View of the split top die shown in Figure 3;

Figure 5 is an enlarged plan view of the bottom die, and

Figure 6 is a cross-sectional view taken along line VI- VI of Figure 5.

In accordance with the present invention, the following novel composition is used, having approximately the following proportions by weight: Syenite, 7 /2 lbs.; flint, 1 /2 lbs.; feldspar, 2% lbs.; talc, 1b.; ball clay, 5 lbs.; whiting, 2% lbs.; aluminum hydrate, /2 lb. and barium carbonate, 5 grams. The above ingredients may be increased or decreased by an amount of about Without seriously affecting the characteristics of the final product. However, a composition of the order of that indicated above is a preferred one for obtaining a product having relatively high shatter resistance as well as having characteristics which are almost identical to those of china as distinguished from earthenware, such as translucency, etc.

The above powdery composition may be thoroughly mixed by placing it in an agitator and mixing it with water over a period of about six hours. A suitable ratio is of the order of 800 pounds of dry mixture to 7 gallons of water. After thoroughly mixing with water, the liquid composition is passed through a screen of fine mesh, perr 2,779,989 Patented Feb. 5, 1957 haps of the order of 120 to 140 standard mesh screen size so as to screen out impurities including magnetic material. The liquid composition passing through the screen is deposited in a reservoir, such as a well hole or sump, where further agitation is continued for about two hours, after which the liquid mass is pumped into a filter press of any conventional construction. A conventional type of press has stacked pressing elements with alternate layers of material to be pressed, each of which is surrounded by a burlap sack so that as the pressing elements come together, water is squeezed out through the burlap sacks so as to form a product in leaf form, that is, a plurality of disc-shaped leaves which are comparatively dry or in cake form. Thereafter, these leaves or cakes are placed in a conventional grinding and dust mill wherein they are ground into small particle size and blown through screens of about A1 size or perhaps less, thus producing somewhat dry particles having just enough moisture to permit subsequent molding in a hydraulic press.

A suitable press for carrying out the pressing or molding operation of the present invention is one such as shown in the drawings. Referring more particularlyto Figures 1 and 2, numeral 1 denotes a bottom die, the details of construction of which are more clearly shown in Figures 5 and 6, and numerals 2a and 2b denote the component parts of the split upper die, the details of construcice tion of which are more clearly shown in Figures 3 and 4.

The upper die halves 2a and 2b are rigidly fastened to the lower end portions of inner toggle arms 3 and 4. The upper ends of toggle arms 3 and 4 are pivotally mounted by pins 5 and 6, respectively, to selective holes disposed along a guide bar 7. The end portions of guide bar 7 are guided within vertically disposed slots 8 formed in the frame 9 of the press. The bottom die 1 is rigidly secured on a cross member 10 of the frame. Motive power for moving the upper die halves vertically upwardly or downwardly is provided by a hydraulic cylinder 11 which contains a piston (not shown) connected to a piston rod 12, the lower end of which rod has secured thereto a cross pin 13 pivotally secured to actuating rod 14. A vertically extending groove 14a is provided in the lower portion of actuating rod 14 and through which extends a pin 15 which extends through toggle arms 16, the lower ends of which toggle arms are pivotally mounted by pins 17 to the lower ends of toggle arms 3 and 4. At the extremities of toggle arms 16, there are pivotally mounted rollers 18 which may be in the shape of pulleys and which are adapted to roll along the perimeter of cam blocks 19.

In operation, after the moldable composition has been introduced in the bottom die 1 and driving motor 35 has been started, a start-cycle button 20 is depressed which completes an electrical circuit between a switch 33 and solenoid 22 which actuates a hydraulic valve 23 so as to establish a fluid connection and direct flow of a hydraulic fluid from pump 24 through valve 23 by way of tube 25 which is connected to the top end of hydraulic cylinder 11, therefore causing the piston within the cyl inder to descend at a rate of speed determined by the.

cubic displacement of pump 24. As the piston rod 12 moves downwardly, it lowers actuating rod 14 together with the toggle assembly so that after a predetermined lowering of the actuating rod, the rollers 18 will roll along the cam blocks 19 and move inwardly towards each After the cup has been pressed into shape, and cam dog 27 which is secured to guide bar 7 has actuated the lower switch 28, an electrical circuit is completed through solenoid 29 which will actuate a hydraulic valve 30 and complete a fluid connection between pump 31 and tube 32 to the lower end of hydraulic cylinder 11, causing the piston therein to rise and actuating rod 14 to ascend at a rate predetermined by the cubic displacement of the pump 31. After actuating rod 14 has ascended about two inches to a predetermined level, that is, after cam rollers 18 have reached the top of cam block 19 so as to move outwardly, the upper die halves 2a-2b will be spread apart by means of the toggle arms at which time the pressed cup is ejected. The operator may slip his fingers under the ring of the cup to catch it upon opening of the upper die halves. After actuating rod 145 has ascended suflflciently so that cam dog 27 on the guide bar 7 engages the upper switch 33, another cycle of press operation will be started without the necessity of depressing the start button 20, that is, a circuit will be completed to solenoid 22 causing energization thereof and operation of hydraulic valve 23 to start again the cycle described hereinabove. Automatic cycling will continue until the stop-cycle button 34 is depressed which interrupts the electrical circuit between upper switch 33 and solenoid 22.

The respective pumps 24 and 31 are driven by a motor 35 driving through a suitable coupling 36.

After the cup has been pressed into shape by the dies of the press, it may be immediately decorated, if desired, and dipped in any suitable pottery glaze so as to seal the outer pores, and placed in a kiln and fired up to a temperature and for a period of time corresponding to a cone of about to 7, instead of a much higher cone rating as normally required. An important feature of the invention resides in the fact that the pressed cup as received from the hydraulic press need not be set to dry or age over a period of time and instead may be immediately placed in the kiln. The temperature of the kiln need therefore be raised to a temperature of about 1850 to 2150 F., instead of the usually required higher temperatures for glazing and baking china.

The cup or other article when removed from the kiln has outstanding characteristics, particularly with respect to shatter resistance and translucency, the latter giving it the characteristic of china, which translucency is aided substantially by the addition of barium carbonate to the mixture. The aluminum hydrate contributes to the hardness and shatter resistance of the article. Of course, if neither a high degree of shatter resistance or translucency is desired, the aluminum hydrate and barium carbonate may be omitted or added in smaller amounts.

As described hereinabove, by making the upper dies Za-Zb in the form of split members or halves, it is possible to press articles having handles thereon in a single pressing operation instead of requiring a separate operation for molding the handle which is later adhered to the molded cup portion. Of course, if other articles than a cup are to be pressed, the dies may be correspondingly shaped, such as, for example, plain bowls which require no handle portion.

Thus it will be seen that in accordance with the present invention, there is provided a novel hydraulic press involving dies of such shape to enable pressing of cups and other pottery were with or without handles or the like by a single pressing operation, thereby greatly speeding up the pressing operation; and in accordance with the 4 present method and composition used, there results a finished pottery product greatly simulating china, that is, having various desirable characteristics of china, such as translucency, and in addition a much greater shatter resistance than ordinary china, therefore resulting in a greatly superior china-like product which can be manufactured at costs comparable to those for manufacturing ordinary earthenware.

While a single embodiment of the present invention has been illustrated and described, it will be understood that this is by way of illustration only, and that various changes and modifications of the invention may be made within the contemplation of the invention and within the scope of the following claims.

What is claimed is:

1. A hydraulic press for pressing pottery ware in the shape of cups and the like, comprising a stationary die having an upstanding central core portion surrounded by a key hole shaped cavity, a movable split die comprising two semi-circular die halves having radial extensions, which halves when closed together fit into said cavity, said split dies having extensions with registering holes extending laterally therethrough for forming the handle of the cup and hydraulic means for moving said split die halves into the cavity of said stationary die.

2. A hydraulic press for pressing pottery ware and similar articles having integral handles, comprising a stationary lowerdie having an upstanding central core surrounded by an annular mold cavity having a radially outward extension, an upper split die having a corresponding shape so as to fit into said cavity and shaped so as to form an inverted cup with a perforated handle, toggle means to which the elements of said split die are fastened, cam means disposed on opposite sides of the press for controlling the movement of said toggle means so that upon a predetermined lifting of said split die, the elements thereof will be moved apart and upon a predetermined lowering, said elements will be moved together, hydraulic power means including a hydraulic cylinder having a piston for moving said toggle means vertically upwardly and downwardly, a guide bar secured to said toggle means and to said piston and having end portions which are guided by slots in opposite sides of the frame of said press, a pair of hydraulic pumps, each having a hydraulic valve, and automatic means for reciprocating said split die in a vertical direction, including electrical control means responsive to the movements of said toggle means with respect to said cam means to selectively cause one of said pumps to force hydraulic fluid through one of said valves to one end of said hydraulic cylinder or to cause said other pump to force hydraulic fluid through'the other hydraulic valve to the other end of said hydraulic cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 145,144 Baggs Dec. 2, 1873 162,216 Brockunier Apr. 20, 1875 520,294 Boch May 22, 1894 1,596,059 Mansir Aug. 17, 1926 1,637,708 Porter Aug. 2, 1927 1,794,556 Skidmore Mar. 3, 1931 1,881,061 Pearne et al. Oct. 4, 1932 2,159,349 Bennett May 23, 1939 2,260,000 Burgess et al. Oct. 21, 1941 2,310,068 Emerson Feb. 2, 1943 

